I have an amazing espalier rosebush in my backyard this year that is setting records with the sheer amount of blooms on it. Unfortunately it’s also suddenly covered in black spot fungus, and needs some major help right now.
Black spot is caused by a fungal infestation that occurs in wet locations, or humid places. It can be triggered by late evening watering, or misting sprinklers, and it spreads rapidly on roses if it’s not caught right away and pruned out. For bushes with major black spot problems a store-bought anti-fungal spray, or an application of horticultural oil can work adequately, but for the DIYers like myself, a home remedy will fix the problem and save you the gas and pocket money.
- Vegetable Oil
- Liquid Dish soap
- One 25-32 oz. spray bottle (reuse a windex bottle, or purchase a commercial equivalent)
Combine 1/2 a teaspoon of dish soap with 1/2 a teaspoon of vegetable oil in your spray bottle, and fill completely with water, leaving only enough room for the straw and cap to screw on without overflow. Lightly shake, and then liberally spray this anti-fungal spray all over your roses, leaves, blooms and all.
For the next three weeks apply this recipe to your roses, and you should see results quickly. For added benefit, if you wash your dishes by hand in the sink you should transfer the soapy sink water to a pail or watering can, and use that water to hydrate the base of your rose bushes. Gentle soapy water can temporarily kill any fungus living in the mulch, or the soil at the base of the plant, and prevent the fungus from attacking your roses again in the near future.